Polycarbonate preparation method

摘要

Provided is a polycarbonate preparation method, comprising the following steps: a) mixing a phenoxide water aqueous solution of a bisphenol and/or a polyphenol with a phosgene and an inert organic solvent, reacting, and generating a polycarbonate oligomer; b) highly emulsifying the oligomer by reinforced micromixing to form a stable emulsion; and c) introducing the emulsion into a polycondensation reactor for a chain extending reaction, separating and finally obtaining the polycarbonate. Through the reinforced micromixing, the present method can prepare the high-molecular-weight polycarbonate without any catalysts, thus simplifying the post-treatment process of the product and improving product quality.

主权项

1. A method for preparing a polycarbonate, wherein a continuous two-phase interfacial polycondensation process is utilized, the method comprising:
a) mixing a phenoxide aqueous solution of a bisphenol with a phosgene and an inert organic solvent in a mixing reactor, reacting and generating a polycarbonate oligomer having an average polymerization degree of from 1 to 20; b) highly emulsifying the oligomer obtained in step a) by reinforced micromixing to form a stable water-in-oil emulsion, in which the average droplet diameter of the dispersed phase in the emulsion is less than 300 μm, wherein a small quantity of an alkali metal hydroxide aqueous solution is added before the oligomer is emulsified, and the reaction course has a pH value maintained from 8.5 to 14; and c) introducing the stable emulsion obtained in step b) into a polycondensation reactor for a chain extending reaction to form a high-molecular-weight polycarbonate solution, finally demulsifying and purifying the reaction solution, thereby obtaining a polycarbonate resin, wherein no catalyst is used during the whole continuous two-phase interfacial polycondensation process.